【作者】 王丁科；

【导师】 阎萍；

【作者基本信息】 甘肃农业大学 ， 动物遗传育种与繁殖， 2009， 硕士

【摘要】 将IGF-Ⅱ基因和IGF-ⅡR基因作为控制牦牛生长发育性状主基因的候选基因,采用PCR-SSCP技术对五个不同牦牛群体(大通牦牛、青海高原牦牛、天祝白牦牛、甘南牦牛、新疆巴州牦牛)共380个个体的IGF-Ⅱ基因和IGF-ⅡR基因的多态位点进行了检测,对具有SSCP多态性的片段进行测序,找出突变位点,分析了因突变产生的不同基因型与牦牛生长性状的关系,以期寻找可行的遗传标记,从分子水平上为牦牛育种提供理论依据。研究结果及结论如下:(1)在牦牛IGF-Ⅱ基因的第7内含子发现多态,该多态位点由一对等位基因A、B控制,91 bp处碱基C→T的突变使得由野生型的B等位基因变为A等位基因。在大通牦牛、青海高原牦牛和新疆牦牛3个牦牛群体中B等位基因为优势等位基因,BB型为优势基因型,基因型的分布处于Hardy-weinberg平衡状态。而在另外2个群体中则以AB型为优势基因型,基因型分布极不平衡。(2)在牦牛IGF-Ⅱ基因的第8内含子发现多态,该多态片段330 bp处G→C和358bp处A→G的突变使得由野生型的B等位基因变为A等位基因。各群体中均以BB基因型和B等位基因为优势基因型和优势等位基因,基因型的分布仅在新疆牦牛群体中呈现出轻度不平衡状态,而在其它4个群体均表现出平衡状态。(3)IGF-Ⅱ基因第8内含子与体重性状呈显著的相关性,AA型个体体重极显著高于BB型个体。在育种过程中,可以将该片段作为候选基因用于标记辅助选择,选择AA型个体有望提高后代的平均体重。(4)在牦牛IGF-ⅡR基因的第11内含子发现多态,该片段124 bp处T→C和172 bp处C→T的突变使野生型的B等位基因变为A等位基因。在大通牦牛、甘南牦牛和新疆牦牛3个群体中未发现B等位基因的存在,而在天祝牦牛和青海高原牦牛2个群体中虽然有发现,但基因频率很低。数据分析发现该位点与体重、体高、体斜长和胸围等性状无显著相关性。更多还原

【Abstract】 Using IGF-Ⅱgene and IGF-ⅡR gene as main effect candidate gene of growth and development traits in yaks, polymorphism of IGF-Ⅱgene and IGF-ⅡR gene in 380 yaks that come from 5 deferent breeds(Datong Yak, Qinghai plateau Yak, TianzhuYak, Gannan Yak and breeding spices Xinjiang yak) was analyzed by PCR-SSCP, and the PCR products with polymorphism fragments were sequenced to detect single nucleotide polymorphism. The polymorphism of IGF-Ⅱand IGF-ⅡR and the relationship between polymorphism and yak partial production traits were studied in order to find a theoretical foundation for Yak’s growth and development, the results show that:(1) The polymorphism of PCR-SSCP was found in the 7th intron of the yak’s insulin-like growth factor 2 gene, the result was detected that The polymorphism is controlled by a pare of allele A and B. The transition of C→T at 91 site of intron7 precipitated the replacement of B→A. Allele B and gene type BB were the superiority gene and gene type in Datong Yak , Qinghai plateau yak and Xinjiang yak. The disposition of gene type was consistent with Hardy-Weinberg balance. Gene type AB was the superiority gene type in the other two groups and the disposition of gene type was not balance.(2) The polymorphism of PCR-SSCP was found in the yak insulin-like growth factor 2, the result show that the transition of G→C at 330 site and A→G at 358 site of intron8 precipitated the replacement of B→A gene type BB and Allele B were the superiority gene type and superiority gene in all five groups. Only in Xinjiang Yak, the disposition of gene type was not balance, but they were balance in the other four groups.(3) IGF-Ⅱgene intron8 was close with the trait of body weight, the result of analysis showed that allele A has higher body weight than allele B. at the progress of animal breeding, IGF-Ⅱgene could be used by marker associate selection as a candidate gene of body weight. The body selected by allele A could enhance filial body weight.(4) The polymorphism of PCR-SSCP was found in the intron 11 of insulin-like growth factor receptor 2 gene, the result showed that the transition of T→C at 124 site and C→T at 172 site precipitated the replacement of B→A. Allele B was not found in Datong Yak, Gannan Yak and Xinjiang Yak. Though allele B was found at the other two groups, gene frequency is very low. The result of analysis showed that this site was not close with the traits of body weight, height, body length and chest girth.更多还原